Rear derailleur Shimano DURA-ACE Di2 RD-R9150 SH 11-speed

DURA-ACE R8050 Di2 derailleurs blend powerful performance with precise shifting that remains crisp and consistent over time.SHIMANO synchronized shiftLow profile rear derailleur designErgonomic shifting operation without stressRace endurance for less damage in crashMaintains compact and smooth appearanceShadow RDSS compatible with cassettes: 11-25T to 11-30TPulley cage: SS (short)Total capacity SS: 33TSmallest sprocket SS: 11THighest difference of chain wheel SS: 16TSmall Sprocket Size Max.: 14 toothWeight: 197 gDirect attachment11T Pulleys with sealed bearings1 E-tube portFirmware update by E-TUBE ProjectFluoric coated link bushings: 4Di2 - The advantages of Di2 (Digital Integrated Intelligence) are clear for everybody who has tested it: changing gears becomes easier, effortless and faster by simply touching the shift buttons. Control at the top of your fingers. Additional benefits include an automatic trimming front derailleur, unmatched precision plus super easy installation and adjustment. This allows automatic chain guide movement in response to the gear position of the rear derailleur. There is no more need for concentration on trimming when riding. The mechanism rear derailleur, SHIMANO SHADOW RD, is intended for more aggressive riding. Its super low profile design carries many benefits. Because of its low profile and single tension construction, the derailleur does not hit the chain stay in rough riding conditions. The result is smooth and silent performance.SEIS - innovative shift technology based on the SHIMANO INDEX SYSTEM (SIS) that has proved its superior gear changing characteristics over the years. The big difference is that in this case, the shifting action is provided for by electronics instead of mechanics. This electronic shifting system has been extensively tested over past two years by several professional riders in all conditions possible, such as rain, mud, low temperatures, cobble stone roads and combinations of all of these at the same time. Shifting is executed by simply pressing the button. No power is needed to shift, which gives important advantages since it is easier now to always keep a tight grip on the handlebar and to keep your concentration on riding instead on shifting. The shift system allows accurate and effortless shifting in difficult circumstances for example when you have cold hands or when you are completely exhausted. Furthermore, the shifting performance will never be affected by contaminated or stretched cables since the shifting signal is transferred electronically. The operating buttons work similarly to mechanical DUAL CONTROL LEVER so you don’t need to re-program your mind for the SEIS.Important: All Shimano Di2 electronic components require the same firmware version. In order to diagnose, read or update firmware, optional device is needed. Operating components with different firmware version may cause malfunction or loss of function.